Calendar APIs come in all shapes and sizes, each with different authentication flows and different data models. Making sure that your application supports all of them can be a long and difficult process. This is where the One Calendar API hopes to make a difference.

One Calendar is an API that wraps around commonly used calendars, such as Google Calendar and Microsoft Exchange, and was developed by the team behind the One Diary app.

Adam Bird, CEO of One Diary, tells us: “I was frustrated with how I couldn’t use calendars to run my life because it was nigh on impossible to get a view on what other people important to me were doing.”

While searching for a solution, they discovered that existing calendar APIs were not easy to interact with, nor to combine. So One Diary decided to solve the problem themselves by building the One Calendar API. “But,” says Adam, “the intention has always been that this is something we offer to both app developers as well as in-house developers to integrate with in-house systems”.

One Diary’s vision is to provide something simple and straightforward: a ‘Stripe for calendars’, perhaps. If you’re not familiar with Stripe, its API allows any website or developer to start accepting payments online through the addition of just a few lines of code. The One Calendar API uses the same approach employing a common data model and authentication and authorisation flows for all supported calendars. This will allow you to focus on building your app without worrying about the overhead of developing and maintaining custom calendar integrations.

A great feature of the API is the addition of webhooks. One Calendar will send you notifications when events are created, updated or tagged, which you can then handle in your application. The feature, which is currently still in beta, has huge potential for shaping whole new interactions between calendars and apps.

The API currently offers support for Google Calendar, iCloud, Office 365 and Exchange. The company says more services will be added in the near future, with Outlook.com and Yahoo as primary candidates for the personal calendar market, and Sharepoint and Salesforce calendar integration for the corporate market.

One Calendar is currently in invite beta. You can request access through the website.